Draft gear



June 18, 1940. c, PlERCE AL 2,205,066

DRAFT GEAR Filed Feb. 2, 1939 3 Sheets-Sheet 1 ATTORNEY.

R. C. PIERCE ET AL.

DRAFT GEAR Filed Feb. 2, 1939 June 18, 1940.

3 Sheets-Sheet 2 ATTQRNEY.

June 13, 1940- I R. c. PIERCE ET AL DRAFT GEAR Filed Feb. 2, 1939 3Sheets-Sheet 5 7720 CPgs/te,

rzd P Jazz/2e,

ATTORNEY.

Patented June 18, 1940 UNITD STATES PATENT OFFHCE f Raymond C. Pierce,Chicago, 11]., and Edmund P.

Kinne, Alliance, Ohio, assignors, by mesne assignments, to said PierceApplication February. 2, 1939, Serial No. 254,134

' 40 Claims. (01. 2'1e-34 This application is a contiiIuatiOmin-part ofour copending application, Draft gear, Serial No. 214,410, filed in theUnited States Patent Office June 18, 1938. I

Our invention relates to a shock absorbing mechanism for railway cars ofthe form generally designated a draftgear of the barrel .type where inthe mechanism consists of an outer housing of generally cylindricalforin with a compression spring enclosed therein and an outwardlyflaring open end wherein is received what issometirnes known as a clutchmechanism.

Generally speaking, the object of our invention is to devise such astructure wherein substantially greater friction absorbing capacity willbe developed than is required under the present standards, thusproviding a shocl; absorbing mechanism capable of withstanding thesubstantially heavier shocks resulting from increased train loads orhigher speeds. v

A further and more definite object of our invention is to devise a draftgear of the barrel type wherein a plurality of friction shoeswill befitted within'the barrel and accommodated for engagement with the innerand outer'followers by insertsof a form peculiarly adapted to facilitateaccurate seating of parts without great refinement of manufacturingprocesses.

In ordinary gears of this clutch type the frictional resistance obtainedis relative to the wedging angle with which the follower wedge engagesthe shoes. In such gears increase'of this angle beyond the criticalpoint is strictly limited by the tendency of the gear to stick. In, ournovel gear this wedging angle may be increased to a much greater extentinasmuch as our novel construction offsets the sticking tendencyotherwise present. Among the objects of our invention, therefore, is thepurpose to design a clutch type gear which will permit the developmentof substan tially high friction absorbing capacity while at the sametime permitting free release.

Another object of our invention is to devise a draft gear which willdevelop a relatively high capacity in the initial portion of the stroke.The A. A. R. standard requires that 25 percent of the capacity bedeveloped in the first half of the stroke. Our purpose is to develop amuch greater portion of the capacity in the first half of the stroke,thus enabling us to avoid excessive capacities at the end of the strokeand shocks resultant therefrom.

Our invention also contemplates such a draft gear as that abovedescribed wherein the spring cap is integrally formed with the innerfollower wedge and wherein said follower wedge is interlocked with theseveral shoes in such manner as to obviate relative rotationtherebetween.

Our invention also comprehends such a gear;

as that above described wherein the inner fol- 5 lower wedge hasabutment with the several serts seated against the respective shoes andtransmits the spring reactions directly to said inserts through whichsaid reactionsmay be further carried to the respective shoes and to the10 outer follower wedge.

Another object of our invention is. to devise a truss type draft gearwherein forces from the outer follower wedge will-be transmited to aseries of shoes through a series of inserts, one in- 15 sert beingassociated with each shoe, and wherein the engaging surfaces between theouter follower wedge and the insert will be of cylindrical form with arelatively long radius and the,

engaging surfaces between each insert and the adjacent shoe willlikewise be a cylindrical surface with a relatively short radius.

A further object of our invention is to design a gear as abovedescribedwherein the inserts;

of the several shoes will maintain. a constant bearing against the innerfollower wedge under all conditions of normal operation of the gear.

Figure l is a longitudinal sectional view of our novel form of draftgear, the section being taken substantially in the horizontal planebisecting the gear longitudinally and as indicated by the line l--l ofFigure 2;

Figure 2 is an end elevation, partly in section,

the section at the lower portion of the figure heing taken in thetransverse plane substantially as indicated by the line 2-2 of Figure 1and the section at the upper left of the figure being takensubstantially in the transverse plane indicated by the lineAA of Figure1;

Figure 3 is a plan view of the spring cap, 4

the view being taken from the outer face thereof;

Figure 4 is a side elevation of the spring cap or inner follower wedge;

Figure 5 is a plan View the view being taken from the inner facethereof; Figure 6 is an end elevation of the shoe, the View being takenfrom the outer end;

Figure 7 is a sectional view in a plane bisecting the shoe through itslength and substantially in the plane indicated by the line 1-7 ofFigure 5;

Figure 8 is a sectional view taken diagonally through the friction shoeand substantially in the plane indicated by the line 88 of Figure '7;

of one of the shoes, 45

Figure 9 is a plan view of the outer follower Wedge, the View beingtaken from the inner face thereof;

Figure 10 is a side elevation of the outer fol lower wedge;

Figure 11 is a plan view of the insert, the view being taken from theouter face thereof;

Figure 12 is an end elevation of the insert, the view being taken fromthe upper end;

Figure 13 is a side elevation of the insert;

Figure 14 is a fragmentary view corresponding in general to the Viewshown in Figure 1 of a modified form of our novel draft gear, the viewbeing taken substantially in the horizontal plane bisecting the gearlongitudinally and as indicated by the line l4-i4 of Figure 15;

Figure 15 is an end elevation corresponding in general to the view ofthe previous modification shown in Figure 2 and partly in section, thesection at the bottom of the figure being taken in the transverse planesubstantially as indicated by the line [5-45 of Figure 14, and thesection at the left of the figure being taken substantially in thetransverse plane indicated by the line B-B of Figure 14; and

Figure 16 is a longitudinal section through the tongue and grooveengaging surfaces of the inner spring follower and one of the shoes, thesection being taken substantially as indicated by the line l6-l6 ofFigure 14.

Describing our invention in more detail, the housing 2 is of a form moreparticularly described and shown in United States Letters Patent No.2,160,417, issued May 30, 1939, in the name of William C. Hedgcock,wherein Figure 8 shows the particular form of housing here used. Thehousing 2 is of generally cylindrical form having the base 4 and theside walls 6 and the inner surface at the open end of the housing isflared outwardly in the well known manner as best seen at 8 (Figure 1).Centrally formed on the inner face of the base 4 is the hollow stud ID,the walls of which define the cavity I2 within which may be received thehead 14 of the retaining bolt 16, the opposite end of said boltreceiving the threaded nut is. Within the housing is positioned thelarge outer compression spring 20 seated at its inner end against thebase 4 and retained in position by the stud ID. The auxiliary spring orinner compression spring 22 is seated at its inner end against the innerface of the stud l and the outer ends of both springs 20 and. 22 areseated as at 24 and 26 against the spring cap 23, the inner spring beingseated in a shallow cavity 28 formed on the inner face of the spring capas best seen in Figure 1.

In addition to the combination spring cap and inner follower wedge 23,the clutch mechanism comprises three shoes 30, 30 symmetrically arrangedaround the inner face of the housing, an insert 32 associated with eachshoe 30 and the outer follower wedge 34. It may be observed that thereacting force is delivered from the compression springs 20 and 22through the inner follower 23 to the inserts 32 and thence aredistributed against the several shoes 30, 30 arranged around theperiphery of the housing and to the outer follower wedge 34. The shoes30, 30 have no engagement with either follower wedge except at its innerend each shoe is interlocked with the inner follower wedge 23 by atongue and groove fit as at 36 (Figure 1) best understood from aconsideration of the detail showings of these parts in Figures 3, 4, and7.

The arrangement of the shoes around the housing is best seen in Figure 2where it may be observed that each shoe 30 has a generally V-shapedouter face fitted into a surface of complementary shape formed on theinner periphery of the housing. The housing is thus hexagonal in sectionwith each shoe occupying substantially one-third of the periphery orsome thing less than one hundred twenty degrees. The manner in which thevarious parts of the clutch mechanism seat against each other will bebest understood by a consideration of the detail structures of theseparts.

The form of the combination spring cap and inner follower wedge is shownin Figures 3 and 4. It may be observed that the base 38 is generallyhexagonal having on its inner face the beforementioned shallow circularcavity 28 serving as positioning means for the inner spring 22 andhaving on its outer face the large boss 40 with the central opening 42along the axis of the gear for reception of the retaining bolt I6. Theboss 49 is of generally cylindrical form presenting on its outer surfacethe three diagonally arranged fiat faces 44, 44 symmetrically arrangedaround said boss and serving as abutments against which may be seatedthe inner ends of the inserts 32, 32 as at 46 (Figure 1). Alsosymmetrically arranged around the base 38 are the slightly raisedportions or tongues 48, 48 aligned respectively with the faces 44, 44,said tongues being received in corresponding grooves 50, 50 (Figure 5)formed on the inner edges of the shoes 30, 30 and serving to interlocksaid shoes with said inner follower wedge in a manner to prevent theirrelative rotation.

The detail structure of each shoe is shown in Figures 5 to 8, inclusive,and consists in general of a solid body of metal, V-shaped incross-section and generally rectangular in plan with a slightly greaterwidth at its outer end than at its inner in order to accommodate theshoe structure to the flaring open end of the barrel or housing 2. Theshoe has the V-shaped outer face with an included angle of approximatelyone hundred twenty degrees between the two portions thereof,

the several shoes thus being accommodated in the complementary seatsformed on the inner face of the open end of the barrel. Each shoe has onits inner face the cylindrical surface 52 defining a relative shallowcavity designed to accommodate the complementary surfaces 54 (Figure 12)formed on the outer face of the insert 56. The upper extremity of theshallow insert receiving cavity is defined by the shoulder 58 at theupper end of the shoe. The back wall of the shoe is extended beyond theheavy central body portion 60 (Figure '7) in the projection 62, andtransversely across the bottom of said body portion 60 at the middlethereof is formed the previously mentioned shallow groove 50 for thereception of the complementary tongue 48 formed on the outer face of thespring cap or inner follower wedge.

The inserts 56, 56 are of identical form, each being a solid body ofmetal of generally rec tangular form and greater width than length.having at its inner end the flat surface 62 for abutment against a face44 of the inner follower wedge; presenting also an outer cylindricalsurface 54 complementary in form to the shoe surface 52 against which itis seated as previously described and having also a flat inner face 64for abutment against the outer follower wedge. When the parts areassembled, each insert 32 has a clearance from the shoulder 58 at theouter iegcosgoce end of theassociated "shoe as'best seen at 66(Figure 1) The outer follower wedge 34 is of cup -like' form as shown inFigures 9-and l0,"the"o,uter' portion tional follower block, the'outerperimeter of said portion being defined bythe annular fiangel extendingbeyond the annular walls-H. 'II. Cen trally formed in the outer faceof'this'follower wedge is the cavity 12' within which may be receivedthe projecting end of the retaining bolt It with its associated threadednut,-said bolt'eX- tending through the opening 'Ifi'cen'trally formed inthe follower wedge. At its inner end this follower wedge presentsthe'threefl'at faces 16.16 symmetrically arranged there-around, each ofsaid faces being designed to abut'the inner face it of the associatedinsert, the engagement therebetween being best shown at I8 (Figure l) Wehave discovered that the length of theradius determining the cylindricalsurface on the back of each insert 32 and on the inner face of each shoe30 is determinative of the rotational stability of the insert underoperating conditions; in other words, to preventrotation'of the insertwith respect to the associated shoeagainst which it is seated, it isnecessary that the radiusfrom which the before mentioned cylindricalsurface is described be less than the distance X (Figure 1) lying in aplane bisecting said cylindrical surface normally thereto, andintersecting the axis of the gear.

It may be noted further (Figures 1 and 13) that the included angle Mshould be less'than ninety degrees for best operation 'of thisgear andlikewise the included angle N should'be equal to or greater than a rightangle.

The modification shown in Figures l4and 15 differs from that previouslydescribed in that the engaging surfaces between the outer follower wedgeand the inserts are of cylindrical form instead of flat. The housing I02is like that of the previous modification having aboutits periphery atthe open end the inner friction surfaces generally V-shaped againstwhich are' seated the shoes tilt, IM and associated with each shoe is aninsert I06, the insert having engagement with the shoe along thecylindrical surface 108 similar to that of. the previous modification.The opposite surface of each insert engaging the follower H2 asindicated at H0 in this modification is a shallow cylindrical surfaceinstead of a flat surface as in the previous modification. The charactorof this shallow cylindrical surface andits relative curvature ascompared with the curvature at the opposite side of the insert as shownat its is best seen from a consideration ofthe sectional View at thebottom of Figure 15. The follower I H? is otherwise similar to thatof'the previous modification, having the outwardly facing cavity H4receiving the retaining'bolt and nut assembly H6, said boltextending'through the centrally formed opening H8 in the spring capfollower 20. The said spring cap follower has a flat face abutment as atI22 with the inwardly di rected bottom surface of each insert I and thespring cap follower likewise has a tongue and groove engagement witheach shoe I04, the groove indicated at I24 and the tongue at IZt'in theview shown in Figure 16, said tongue and groove engagement being similarto that described for the previous modification. The inner face of thespring cap follower abuts the large compression spring I28 on an annularsurface about its seat I30.

the shoes. squeezed between the outer follower and the "periphery asindicated at I30 and likewise abuts *the'relatively small compression:spring I32 asaat I34 on the'seat offset from thebefore'mentioned Thelengthof the radius for the cylindrical surface on the back of eachinsert I06 is determined '-as described for the previous modificationand. the radius at the opposite side of the insert where it engages acomplementary surface on the'outer follower is of much greater length asclearly seen from a consideration of sections therethrough as indicatedat I08 and H0 (Figure The radius defining the surface at H0 shouldbesuch as to produce a minimumof curvature on these surfaces, but toaccomplish the desired results" must be cylindrical as distinguishedfrom flat.

Our theory of the method of operation ofour novelgear is as follows:

'When the parts are in released position as shown in Figure l theoutward pressure of tha springsis effective to retain the clutch partstightly wedged in position with the shoes firmly urged against thebarrel and the inserts tightly wedged between the shoes and the innerand cute er followers. 'Because of the relatively sharp angle betweenthe shoes and the inserts the outward pressure of the shoes against thebarrel is greater than would ordinarily be possible in a clutch typegear. When impact is received against the outer wedge follower, theclutch parts are forced into the housing and because the Wedgingsurfaces 8 of the housing are set at a small angle with respect to theaxis of the gear the shoes are forced closer together.

Elasticity of the parts may permit a small amount of inward motionbefore the clutch parts move relative ,to one another but as suchrelative movement begins, other members of the clutch assembly move intothe barrel more rapidly than the wedge follower. due to the beforementioned axial movement of At the same time the insertsare shoes due tothe said axial movement of the shoes, and the inner follower is thusmoved inwardly a.

greater distance. than the outer follower travelsl' This sliding actionas described between the various parts increases the gear capacity.

When pressure is released from the outer wedge follower at the end ofthe compression movement.

'the'outer wedge follower promptly frees itself from the inserts becauseof the relatively fiat angles between said outer wedge follower and saidinserts. With the release of the outer wedge follower the other partsare also free to return to the normal released position under the actionof the compression spring.

It should be noted that the unusually high capacity of our novel gear islargely due to the fact that it permits the use of unusually acuteangles between the inserts and the shoes while" attaining desirablerelease characteristics by the "use of relatively fiat angles betweenthe outer wedge follower and the inserts.

This arrangement of said angles permits the compression spring tofunction efficiently in tightly wedging" the clutch parts together aftereach stroke so that the parts are ready for the next. impact. "Thisresults in a gear which develops a rela- "tively great capacity in theinitial portion of the stroke and enables us to avoid excessive ca-'pacity at the end of the stroke otherwise necessary in order to meetrequired standards. Such excessive capacity at the end of the'stroke'develops shocks harmful to the car structure and ladin'g.

It is to be understood that we do not wish to be limited by the exactembodiments of the device shown which are merely by way of illustrationand not limitation as various and other forms of the device will ofcourse be apparent to those skilled in the art without departing fromthe spirit of the invention or the scope of the claims.

We claim:

1. In a friction absorbing device, a housing, a compression springtherein, clutch means seated in the open end of said housing, and aretaining bolt, said clutch means comprising inner and outer followerwedges, a plurality of shoes symmetrically arranged around the innercircumference of said open end and aligning means associated with eachshoe and having diagonally arranged cylindrical face engagementtherewith and having fiat face engagement with each of said wedges, saidshoes being free of engagement with one of said wedges and havinginterlocking engagement with the other, said interlocking engagementcomprising a transverse slot adjacent the inner edge of each shoe, and aplurality of means on said inner wedge receivable in said respectiveslots thereby preventing relative rotation of said shoes and said wedge.

2. In a friction draft gear of the barrel type, a housing having aflaring open end, a compression spring, clutch means, and a retainingbolt, said clutch means comprising inner and outer follower wedges, aplurality of shoes symmetrically arranged around the inner periphery ofsaid open end, and an insert associated with each shoe for transmissionof thrusts between said shoe and said inner and outer wedges, saidinsert having fiat face engagement with each of said wedges and havingdiagonally arranged cylindrical face engagement with the associatedshoe, the cylindrical face of said insert having a radius less than thatof the line defined by the intersection of longitudinal and transverseplanes bisecting said insert and extending from said cylindrical face tothe longitudinal axis of said gear.

3. In a friction draft gear of the barrel type, a housing having aflaring open end, a compression spring, clutch means, and a retainingbolt, said clutch means comprising inner and outer follower wedges, aplurality of shoes symmetrically arranged around the inner periphery ofsaid open end, and an insert associated with each shoe for transmissionof thrusts between said shoe and said inner and outer wedges, saidinsert having diagonally arranged cylindrical face engagement with saidshoe, said cylindrical face having a radius of less length than that ofa line defined by planes bisecting said insert transversely andlongitudinally thereof and extending from said cylindrical surface tothe longitudinal axis of said gear.

4. In a friction absorbing device, a housing having an open end, acompression spring, clutch means seated in said open end, and aretaining bolt, said clutch means comprising inner and outer followerwedges, a series of friction shoes seated against said housing, andthrust means associated with each of said shoes, said thrust meanshaving diagonal cylindrical face engagement with the associated shoe andhaving fiat face engagement with each of said wedges along planesdefining acute angles with said cylindrical face, said inner wedgehaving means interlocked with each of said shoes to prevent relativerotation of said wedge and said shoes.

5. In a friction absorbing device, a housing, a compression springtherein, clutch means seated in the open end of said housing, and aretaining bolt, said clutch means comprising inner and outer followerwedges, a plurality of shoes symmetrically arranged around the innercircum ference of said open end, and aligning means associated with eachshoe and having diagonal cylindrical face engagement therewith andhaving flat face engagement with each of said wedges, said shoes beingfree of engagement with one of said wedges and having interlockingengagement with the other of said wedges to prevent relative rotationthereof.

6. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each of said shoes in the form of rectangular means ofgreater width than length, said means having diagonal cylindrical faceengagement with the associated shoe and diagonally arranged fiat faceengagement with each of said wedges, said flat faces defining anincluded angle equal to or greater than ninety degrees.

'7. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each of said shoes in the form of rectangular means ofgreater width than length, said means having diagonally arrangedcylindrical face engagement with the associated shoe, diagonallyarranged cylindrical face engagement with one of said wedges, anddiagonally arranged fiat face engagement with the other of said wedges.

8. In a friction absorbing device, a housing having an open end, acompression spring, clutch means seated in said open end, and aretaining bolt, said. clutch means comprising inner and outer followerwedges, a series of complementary friction shoes seated against saidhousing, and thrust means associated with each of said shoes, saidthrust means having diagonal cylindrical face engagement with theassociated shoe and having fiat face engagement with each of said wedgesalong planes defining acute angles with the cylindrical face of saidthrust means.

9. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer Wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each of said shoes in the form of rectangular means ofgreater width than length, said means having diagonally arrangedcylindrical face engagement with the associated shoe and with one ofsaid wedges, and flat face engagement with the other of said wedges,said means tapering from a relatively thick lower end toward the upperend thereof.

10. In a draft gear of the barrel type, a housing having a flaring openend of generally hexagonal cross section, a compression spring housedtherein, friction means, and a retaining bolt, said friction meanscomprising an inner follower, an outer follower, three friction shoeshaving V-shaped outer faces symmetrically seated last mentioned followeragainst said flaring open end, and aligning means associated with eachshoe, said aligning means having diagonally arranged cylindrical faceengagement with said shoe and with said outer follower, and flat faceengagement with said inner follower.

11. In a friction absorbing device, a housing having an open end, acompression spring, clutch means seated in said open end, and aretaining bolt, said clutch means comprising inner and outer followerwedges, a series of complementary friction shoes seated against saidhousing, and thrust means associated with each shoe and having diagonalcylindrical face engagement therewith and with said outer followerwedge, said thrust means having flat face engagement with said innerwedge in a plane defining an acute angle with the cylindricalfacethereof.

12. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, andretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each shoe and having diagonal flat lace engagement withsaid inner wedge and diagonal cylindrical face engagement with saidouter wedge and with each of said shoes, each of said shoes havingadjacent its inner edge means engaging said inner wedge to preventrelative rotation. thereof.

13. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each shoe and having diagonal fiat face engagement withsaid inner wedge and diagonal cylindrical face engagement with saidouter wedge and with the associated shoe, said cylindrical surfacesbeing defined by relatively long and short radii respectively.

14.. In a friction absorbing device, a housing having an open end, acompression spring therein, clutch means seated in said open end, and aretaining bolt, said clutch means comprising inner and outer wedgefollowers, a plurality of friction shoes, and thrust means associatedwith each of said shoes and having diagonal cylindrical face engagementtherewith and with one of said followers, each of said thrust meanshaving flat face engagement with the other of said followers, said shoeshaving means engaging said to prevent relative rotation thereof.

15. In a friction absorbing device, a housing, a compression springtherein, clutch means seated in the open end of said housing, and aretaining bolt, said clutch means comprising inner and outer followerwedges, a plurality of shoes'symmetrically arranged around the innercircumference of said open end, and aligning means associated with eachshoe and having diagonal cylindrical face engagement therewithv and withsaid outer wedge, each of said aligning means having fiat faceengagement with said inner follower and means on said inner followerengaging each shoe to prevent relative rotation thereof.

4 around said housing, inner and outer'follower wedges, and aligningmeans associated with each shoe and having diagonal cylindrical faceengagement therewith and with one of said wedges and having flat faceengagement with the other of said wedges, said other wedge having meansengaging each of said shoes to prevent relative rotation thereof,certain of said cylindrical faces being defined by a relatively longradius as compared with others thereof.

17. In a friction draft gear of the barrel type, a housing having anopen end, a compression spring, clutch means comprising inner and outerfollowerwedges, a plurality of shoes symmetrically arranged within saidopen end, and thrust means associated with each shoe and having fiatface engagement with said inner wedge and cylindrical face engagementwith said outer wedge and with the associated shoe, said cylindricalengagement between the thrust means and shoe having a relatively shortradius as compared with said other cylindrical engagement, each of saidshoes having thrust engagement at spaced areas with said inner Wedgealong flat surfaces at right angles to the axis of said gear.

18. In afriction draft gear of the barrel type, a housing having an openend, a compression spring, clutch means comprising inner and outerfollower wedges, a plurality of shoes symmetrically arranged within saidopen end, and thrust means associated with each shoe and having diagonalflat face engagement with one of said wedges and cylindrical faceengagement with the other thereof and with the associated shoe, saidshoe and wedge cylindrical surfaces having relatively short and longradii respectively, each of said shoes having thrust engagement atspaced areas with said inner wedge along fiat surfaces at right anglesto the axis of said gear.

19. In a draft gear, a housing having a flaring open end, a compressionspring therein, friction means, anda securing bolt, said friction meanscomprising inner and outer follower wedges, a plurality of frictionshoes symmetrically seated against said flaring open end, and meansassociated with each shoe and having diagonal cylindrical faceengagement therewith, said means having diagonal flat face engagementwith each of said wedges along planes defining acute angles with saidcylindrical faces.

20. In a friction gear of the barrel type, a housing, a compressionspring, a clutch mechanism, and a retaining bolt, said clutch mechanismcomprising a series of shoes symmetrically arranged around said housing,inner and outer follower wedges, and aligning means associated with eachshoe and having fiat face engagement with one of said wedges andcylindrical face engagement with the other wedge and with the associatedshoe, said shoe cylindrical face having a relatively short radius ascompared with said wedge cylindrical face, each of said shoes havingthrust engagement at spaced areas with said inner wedge along flatsurfaces at right angles to v the axis of said gear.

21. In a draft gear of barrel type, a housing having an open frictionend, a compression spring, a clutch means comprising inner and outerfollower wedges, a plurality of shoes symmetrically arranged within saidopen end, and thrust means abutting each shoe and extending between saidwedges for thrust engagement therewith, each of said shoes having thrustabutment with the adjacent thrust means and one of said wedges, one ofsaid thrust surfaces being along a diagonal cylindrical surface.

22. In a friction draft gear of the barrel type, a housing having afriction end, a plurality of shoes symmetrically seated therearound, acompression spring, inner and outer follower wedges, and thrust meansassociated with each shoe and extending between said wedges to transmitthrust therefrom to the associated shoes, each of said shoes also havingthrust engagement with one of said wedges on a plurality of spaced areasalong flat surfaces at right angles to the axis of said gear.

23. In a friction draft gear of the barrel type, a housing having afriction end, a plurality of shoes symmetrically seated therearound, acompression spring, inner and outer follower wedges, thrust meansassociated with each shoe and. extending between said wedges to transmitthrust therefrom to the associated shoes, each of said shoes also havingthrust engagement with one of said wedges on a plurality of spaced areasalong flat surfaces at right angles to the axis of said gear, and meanson said shoes engageable with means on one of said wedges to limitrelative rotation thereof.

24. In a draft gear, a housing having an open friction end, acompression spring, a clutch means seated in said friction end andcomprising a plurality of shoes seated around said friction end, innerand outer wedge followers, and independent thrust means extendingbetween said wedge followers and in abutment with said shoesrespectively, each of said shoes also having thrust engagement with oneof said wedges on a plurality of spaced areas along flat surfaces atright angles to the axis of said gear.

25. In a draft gear, a housing having an open friction end, acompression spring, a clutch means seated on said friction end andcomprising a plurality of shoes seated around said friction end, innerand outer wedge followers, independent thrust means extending betweensaid wedge followers and in abutment with said shoes respectively, eachof said shoes also having thrust engagement with one of said wedges on aplurality of spaced areas along flat surfaces at right angles to theaxis of said gear, and means on each of said shoes engageable with meanson one of said followers to limit relative rotation thereof.

26. In a draft gear of barrel type, a housing having an open end withtapering friction surfaces symmetrically arranged therearound, acompression spring and clutch mechanism comprising a plurality of shoesseated against said friction surfaces, inner and outer wedge followers,and a thrust member extending between said followers for each shoe andtransmitting thrusts from said followers to said shoe, each of saidshoes also having thrust engagement with one of said wedges on aplurality of spaced areas along flat surfaces at right angles to theaxis of said gear.

27. In a draft gear of barrel type, a housing having an open end withtapering friction surfaces symmetrically arranged therearound, acompression spring, a clutch mechanism comprising a plurality. of shoesseated against said friction surfaces, inner and outer wedge followers,a thrust member extending between said followers for each shoe andtransmitting thrusts from said followers to said shoe, each of saidshoes also having thrust engagement with one of said wedges on aplurality of spaced areas along flat surfaces at right angles to theaxis of said gear, and means on each of said shoes overlapping means onone of said followers to limit relative rotation thereof.

28. In a draft gear, a barrel having a friction end, a compressionspring therein, and clutch mechanism comprising shoes symmetricallyseated around said end, inner and outer follower wedges, thrust membersextending between said wedges for transmitting thrust therefrom to saidshoes respectively, the engaging surfaces between said thrust means andsaid shoes being of diagonal cylindrical form.

29. In a draft gear, a barrel having a friction end, a compressionspring therein, and clutch mechanism comprising shoes symmetricallyseated around said end, inner and outer follower wedges, thrust membersextending between said wedges for transmitting thrust therefrom to saidshoes respectively, the engaging surfaces between said thrust means andsaid shoes being of diagonal cylindrical form, and means on each of saidshoes engageable with means on one of said followers to limit relativerotation thereof.

30. In a draft gear, a barrel having a friction end, a compressionspring therein, and clutch mechanism comprising shoes symmetricallyseated around said end, inner and outer follower wedges, thrust membersextending between said wedges for transmitting thrust therefrom to saidshoes respectively, each of said thrust members having diagonal flatface engagement with one of said wedges and diagonal cylindrical faceengagement with the other thereof, one of said wedges having thrustengagement with each of said shoes on a plurality of spaced areas.

31. In a draft gear, a barrel having a friction end, a compressionspring therein, and clutch mechanism comprising shoes symmetricallyseated around said end, inner and outer follower wedges, independentthrust members extending between said wedges for transmitting thrusttherefrom to said shoes respectively, each of said thrust members havingdiagonal flat face engagement with both of said wedges and diagonalcylindrical face engagement with the associated shoe, one of said wedgeshaving thrust engagement with each of said shoes on a plurality ofspaced areas.

32. In a draft gear, a barrel having a friction end, a compressionspring in said barrel, and clutch mechanism comprising shoessymmetrically seated around said end, inner and outer follower wedges,independent thrust members extending between said wedges fortransmitting thrust therefrom to said shoes respectively, each of saidshoes having thrust engagement with one of said Wedges on a plurality ofspaced areas, each of said thrust members having diagonal faceengagement with both of said wedges and diagonal cylindrical faceengagement with the associated shoe.

33. In a draft gear, a barrel having a friction end, a compressionspring therein, and clutch mechanism comprising shoes symmetricallyseated around said end, inner and outer follower wedges, independentthrust members extending between said wedges for transmitting thrusttherefrom to said shoes respectively, each of said thrust members havingdiagonal face engagement with both of said wedges and with theassociated shoe, at least one of said diagonal faces having acylindrical form, each of said shoes also having thrust engagement withone of said wedges on a plurality of spaced areas.

34. In a friction gear, a housing having a flaring open end, acompression spring, friction means, and a securing bolt, said frictionmeans comprising inner and outer follower wedges, a plurality offriction shoes symmetrically seated against said flaring open end,thrust means associated with each shoe and having diagonal cylindricalface engagement therewith and with one of said follower wedges andhaving fiat face engagement with the other of said wedges, one of saidfollower wedges having thrust engagement with said shoes.

35. In a friction gear, a housing having a flaring open end, acompression spring, friction means, and a securing bolt, said frictionmeans comprising inner and outer follower wedges, a plurality offriction shoes symmetrically seated against said flaring open end,thrust means associated with each shoe and having diagonal faceengagement therewith and with each of said follower wedges, said innerfollower wedge having thrust engagement with each of said shoes on aplurality of spaced areas.

36. In a friction absorbing device, a housing having an open end, acompression spring, a

' clutch mechanism seated in said open end, and a spaced areas.

retaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes, and thrust meansassociated with each shoe, said thrust means having diagonal cylindricalface engagement with the associated shoe and diagonal flat faceengagement with each of said wedges, one of said wedges having thrustengagement with each of said shoes on 37. In a friction absorbingdevice, a housing having an open end, a compression spring, a clutchmechanism seated in said open end, and a retaining bolt, said mechanismcomprising inner and outer wedges, a plurality of symmetrically arrangedfriction shoes, and thrust means associated with each shoe, said thrustmeans having diagonal cylindrical face engagement with the associatedshoe and diagonal flat face engagement with each of said wedges, one ofsaid wedges having thrust engagement with each of said shoes along aplurality of spaced areas lying in a single plane.

38. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes and thrust meansassociated with each shoe, said thrust means having diagonal cylindricalface engagement with the associated shoe and diagonal face engagementwith each of said wedges, and means on one of said wedges interlockingwith each of said shoes to prevent relative rotation thereof.

39. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes and thrust meansassociated with each shoe, said thrust means having diagonal cylindricalface engagement with the associated shoe and diagonal face engagementwith each of said wedges, and means on said inner wedge interlockingwith each of said shoes to preventrelative rotation thereof.

40. In a friction absorbing device, a housing having an open end, acompression spring, a clutch mechanism seated in said open end, and aretaining bolt, said mechanism comprising inner and outer wedges, aplurality of symmetrically arranged friction shoes,and thrust meansassociated with each shoe, said thrust means having diagonal cylindricalface engagement with the associated shoe and diagonal face engagementwith each of said wedges, and means on said inner wedge interlockingwith each of said shoes to prevent relative rotation thereof, said innerWedge having thrust engagement with each shoe on a plurality of spacedareas on opposite sides of said interlocking means.

RAYMOND C. PIERCE. EDMUND 1?. KINNE.

